1. Field of the Invention
The present invention relates to a portable terminal for providing a Wi-Fi Peer-to-Peer (P2P) function. More particularly, the present invention relates to an apparatus and a method for enhancing a data transmission performance in a power saving mode of a portable terminal.
2. Description of the Related Art
Portable terminals allowing wireless voice communication and information exchange are rapidly becoming necessities of modern life. Early portable terminals merely allowed wireless communication. As portable terminal technologies advanced and wireless Internet was adopted, applications of the portable terminal expanded from the simple phone call or schedule management to include games, remote control using short-range communication, image capturing using an embedded digital camera, and a wireless Local Area Network (LAN) function.
The wireless LAN function provides a communication service such as Internet to the portable terminal (e.g., PDA, notebook computer, etc.) traveling within a certain distance based on an installed Access Point (AP), which is a wireless access device. The initial propagation distance of the wireless LAN was merely 10 m and over the years expanded to hundreds of meters. A transmission rate of the wireless LAN is also improved to transmit and receive mass multimedia.
Recently, Wi-Fi Direct technology has been developed to allow Wi-Fi devices to freely communicate with each other for printing or content sharing with no need for the AP or a router. The Wi-Fi Direct technology may organize a group with a Peer-to-Peer (P2P) group owner and a P2P client using Wi-Fi P2P.
For mobility, the portable terminal uses a rechargeable battery attachable to the portable terminal, as a power supply means. As a result, the portable terminal typically operates with the limited battery capacity.
Accordingly, the portable terminals in the Wi-Fi P2P save their power in a power saving mode. The terminal may enter the power saving mode based on opportunistic power save. When the P2P group owner has no packet to transmit, the P2P client in the group notifies no transmit data and requests data transmission to the P2P clients in the group. Thus, with no data to transmit, the P2P group owner and the P2P client sleep and save power. The power saving mode based on the opportunistic power save reduces power consumption by entering a sleep mode when the device in the group is sleeping.
The terminals may enter the power saving mode based on Notice of Absence (NoA). A beacon transmitted by the P2P group owner delivers NoA information to the P2P client of the group, and the group member enters the sleep mode according to the NoA information. The NoA information includes a sleep start time, a sleep duration, a sleep counter, and a sleep interval. In the NoA based power saving mode, the P2P group owner which controls the group saves the power by prearranging the sleep point.
However, the NoA based power saving mode periodically enters the sleep mode so as to shorten the data transmission time as the sleep mode time increases. As a result, the power may be saved and the data transmission performance may be improved by reducing the sleep mode time. However, a method for setting the sleep duration and interval of the NoA information in the portable terminal is not defined yet. Accordingly, what is needed is an apparatus and a method for enhancing the data transmission performance by adjusting the sleep duration and interval of the NoA information in the portable terminal.